Laparoscopic scissors

ABSTRACT

A laparoscopic scissor instrument can include a scissor assembly pivotally coupled to an elongate shaft. The scissor assembly can be formed of scissor blades having pivot posts thereon. The pivot posts can engage apertures on the elongate shaft, thus eliminating the need for a through-pinned pivot connection of the scissor blades. The scissor blades can also include actuation posts thereon. An actuation mechanism can include a slot to engage the actuation posts and open or close the blades of the scissor assembly. The scissor assemblies described herein can have a relatively low operational height such that they do not extend beyond a diameter of the elongate shaft during opening and closing of the scissor assembly.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/614,605, entitled “LAPAROSCOPIC SCISSORS”, filed Sep. 13, 2012,currently pending, which is a continuation of U.S. patent applicationSer. No. 12/463,973, entitled “LAPAROSCOPIC SCISSORS”, filed May 11,2009, issued as U.S. Pat. No. 8,277,475, which claims the benefit ofU.S. Provisional Patent Application Ser. No. 61/052,046, entitled“LAPAROSCOPIC SCISSORS”, filed May 9, 2008, all of which areincorporated by reference herein in their entireties.

BACKGROUND

1. Field

This application generally relates to laparoscopic scissors and, moreparticularly, to laparoscopic scissors with blades having a paraboliccutting profile and to a mechanism for actuating the blades of thescissors.

2. Discussion of the Relevant Art

Laparoscopic surgical instruments or devices that use actuatable blades,such as laparoscopic scissors are typically activated by some mechanicalmeans. In some cases, the surgical instruments or devices use anactuation rod to translate motion from a handle at one end to a blade atthe opposite end of the device. Common to laparoscopic scissors is anactuation rod that includes a pin that works in conjunction with a slotin the blades. Moving the actuation rod cams the pin in the slot, whichopens and closes the scissor blades.

In previous arrangements, the blades typically have slots proximal to apivot location and, because of this configuration, the proximalportions, or back ends, of the blades are typically relatively large.Thus, with prior laparoscopic scissors, when the blades are in theiropen position, the proximal portions of the blades extend out beyond theoutside diameter of the scissors shaft and look like “wings.” Thishigh-profile extension may be a problem for the user and, in particular,the patient as the extended “wings” can catch on or interfere withtissue or other devices during use.

When used on scissors, these wings can be covered by a plastic shrinktubing to insulate all the metal components during electro-surgicalcautery. However, when the blades are open, the wings can stretch anddeform the shrink tubing. This deformation can be problematic in thatwhen the scissors are withdrawn from a trocar, the deformed tubing maynot relax and it may catch on the end of the cannula, thereby pullingthe trocar out of the patient.

SUMMARY

In general, a laparoscopic scissor instrument is provided having variousaspects addressed to overcome the shortcomings in prior scissorinstruments discussed above and provide certain other advantages. Insome embodiments, the laparoscopic scissor instrument can include ascissor assembly with curved or parabolic cutting blades. In one aspect,a laparoscopic scissor comprises an actuation mechanism and an elongateshaft. The elongate shaft comprises an outer tube and the actuationmechanism comprises an actuation shaft movable within the outer tube.The elongate shaft can be connected to a manipulator, such as a handleassembly, and can have a scissor assembly, such as one including a firstscissor blade and a second scissor blade extending from the elongateshaft. In some embodiments, the first scissor blade has a firstparabolic cutting edge and the second scissor blade has a secondparabolic cutting edge.

In some embodiments, a laparoscopic scissor instrument is providedcomprising a handle assembly, an elongate shaft, a scissor assembly, andan actuation mechanism. The elongate shaft has a proximal end coupled tothe handle assembly and a distal end. The scissor assembly is positionedat the distal end of the elongate shaft. The scissor assembly comprisesa first scissor blade and a second scissor blade. The first scissorblade comprises a distal cutting portion, and a proximal actuationportion. The actuation portion comprises a pivot and an actuationprotrusion. The second scissor blade comprises a distal cutting portionand a proximal actuation portion. The proximal actuation portioncomprises a pivot and an actuation protrusion. The actuation mechanismextends through at least a portion of the elongate shaft and is slidablewithin the elongate shaft. The actuation mechanism operatively couplesthe handle assembly to the scissor assembly. The actuation mechanismcomprises an actuation shaft and a scissor actuator. The actuation shafthas a proximal end and a distal end. The scissor actuator is at thedistal end of the actuation shaft. The scissor actuator engages theactuation protrusion of the first scissor blade and the actuationprotrusion of the second scissor blade.

In other embodiments, a laparoscopic scissor instrument is providedcomprising an elongate tube, an actuator, and a scissor assembly. Theelongate tube has a proximal end and a distal end. The actuator isaxially slidable in the elongate tube. The scissor assembly ispositioned at the distal end of the elongate tube. The scissor assemblycomprises a first scissor blade and a second scissor blade. The firstscissor blade has an interface surface and an opposed surface oppositethe interface surface. The first scissor blade has a cutting portion andan actuation portion. The first scissor blade comprises a pivotprotrusion and an actuation protrusion. The pivot protrusion extendsoutwardly from the opposed surface of the actuation portion. The pivotprotrusion is pivotally coupled to the elongate tube. The actuationprotrusion extends outwardly from the interface surface of the actuationportion. The actuation protrusion is operatively coupled to theactuator. The second scissor blade has an interface surface facing theinterface surface of the first scissor blade and an opposed surfaceopposite the interface surface.

In other embodiments, a laparoscopic scissor instrument comprises ahandle assembly, an elongate shaft, and a scissor assembly. The elongateshaft has a proximal end coupled to the handle assembly and a distalend. The scissor assembly is positioned at the distal end of theelongate shaft. The scissor assembly is actuatable between an openposition and a closed position. The scissor assembly comprises a firstscissor blade and a second scissor blade. The first scissor bladecomprises a distal cutting portion and a proximal actuation portion. Thedistal cutting portion has a curved profile following a generallypolynomial curve. The second scissor blade comprises a distal cuttingportion and a proximal actuation portion. The distal cutting portion hasa curved profile following a generally polynomial curve. The firstscissor blade and the second scissor blade are positioned such that thecurved profiles of the first scissor blade and the second scissor bladecreate a substantially continuous bias force between the first scissorblade and the second scissor blade as the scissor assembly is actuatedbetween the open position and the closed position.

Many of the attendant features of the present invention will be morereadily appreciated as the same becomes better understood by referenceto the foregoing and following description when considered in connectionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of laparoscopic scissors;

FIG. 2 is a side view of a scissor assembly of a laparoscopic scissorsinstrument;

FIG. 3A is a top view of a laparoscopic scissor blade of the scissors ofFIG. 1;

FIG. 3B is a top view of a laparoscopic scissor blade of anotherembodiment of laparoscopic scissors;

FIG. 4A is a perspective view of a scissor assembly of the laparoscopicscissors of FIG. 1;

FIG. 4B is a perspective view of a scissor assembly of anotherembodiment of laparoscopic scissors;

FIG. 5A is a perspective view of a scissor assembly and actuationmechanism of the laparoscopic scissors of FIG. 1;

FIG. 5B is a perspective view of a scissor assembly and actuationmechanism of another embodiment of laparoscopic scissors;

FIG. 6 is a perspective view of a distal end of an embodiment ofactuation mechanism of the laparoscopic scissors of FIG. 1

FIG. 7 is a top view of an embodiment of actuation mechanism of thelaparoscopic scissors of FIG. 1;

FIG. 8A is a perspective view of an interior of an embodiment of handleassembly of the laparoscopic scissors of FIG. 1;

FIG. 8B is a perspective view, partially in cross-section, of aninterior of a handle assembly of another embodiment of laparoscopicscissors;

FIG. 9A is a perspective view of an embodiment of handle assembly toactuation mechanism connection of the laparoscopic scissors of FIG. 1;

FIG. 9B is a perspective view of an embodiment of handle assembly toactuation mechanism connection of another embodiment of laparoscopicscissors;

FIG. 10 is a perspective view of a distal end of the laparoscopicscissors of FIG. 1; and

FIG. 11 is a perspective view of a proximal end of the laparoscopicscissors of FIG. 1.

DETAILED DESCRIPTION

With reference to FIG. 1, a laparoscopic scissors is provided having anelongate shaft 10 with a proximal end 12 connected to a manipulator,such as a handle assembly 20. Extending from a distal end 14 of theelongate shaft 10 is a scissor assembly 30, which, in some embodimentsincludes a pair of scissor blades pivotally movable with respect to oneanother. In some embodiments, the elongate shaft 10 can be sized to fitthrough an access port, such as a trocar cannula, that extends into aninsufflated abdominal cavity for use in a laparoscopic surgicalprocedure. In other embodiments, the elongate shaft 10 can be sized foruse in other surgical environments. In the illustrated embodiment, theelongate shaft 10 comprises an elongate generally cylindrical outertube, although in other embodiments, the elongate shaft 10 can haveother geometries such as square tubes or tubes having eccentric or ovalcross-sectional profiles.

An actuation mechanism 40 (FIGS. 5A, 5B, 8A, 8B) can extend through atleast a portion of the elongate shaft 10 and can operatively couple thehandle assembly 20 (FIGS. 8A, 8B) to the scissor assembly 30 (FIGS. 5A,5B). A proximal end of the actuation mechanism 40 is coupled to thehandle assembly 20 (FIGS. 8A, 8B), and a distal end of the actuationmechanism 40 is coupled to the scissor assembly 30 (FIGS. 5A, 5B).

The elongate shaft 10 in some embodiments is formed of a metallicmaterial and portions of the actuation mechanism extending through thetube in some embodiments are formed of a plastic material. It iscontemplated that in other embodiments, other materials may be used.Where the elongate shaft 10 is made of a metallic material, the elongateshaft 10 can be covered with an electrically insulating material orsheath, such as a plastic material, which in one aspect may be a shrinktubing material.

With reference to FIG. 1, the handle assembly 20 can comprise astationary handle 22 and a movable handle 24. In the illustratedembodiment, through manipulation of the handle assembly 20 (e.g., movingthe movable handle 24 in relation to the stationary handle 22), theactuation mechanism 40 can be longitudinally slid within the elongateshaft 10 to move the scissor assembly 30 between an open and closedconfiguration (FIGS. 5, 8). While the laparoscopic scissors isillustrated as having a handle assembly with a stationary handle and amovable handle, in other embodiments, it is contemplated that otherhandle assemblies can be used with the laparoscopic scissors describedherein, such as, for example, a handle assembly having a slidableplunger, or a handle assembly having two movable handles.

In some embodiments, the laparoscopic scissor instrument can beconfigured to perform electrocautery. In the illustrated embodiments,the handle assembly 20 further includes an electrical connecting post 50(FIGS. 1 and 11) to provide for cauterization of tissue during aprocedure. The electrical connecting post 50 can be attached to thehandle assembly 20 so as to extend at transversely to or generallyperpendicular to an outer surface of the handle assembly 20 and caninclude an electrical conductor such as a spring or wire extending intothe handle assembly 20. The electrical conductor can extend from theconnecting post 50 into contact with the elongate shaft 10 to provideelectrical contact to the scissor assembly 30.

With reference to FIG. 1, the scissor assembly 30 comprises a firstscissor blade 32 and a second scissor blade 34. The scissor assembly 30can be actuated between an open state and a closed state to cut itemssuch as body tissue positioned between the scissor blades 32, 34. Thefirst scissor blade 32 is spaced from the second scissor blade 34 whenthe scissor assembly is in a normal or open state. Conversely, the firstscissor blade 32 is proximate the second scissor blade 34 when thescissor assembly 30 is in an actuated or closed state. The first scissorblade 32 may be considered, although not limited to, an outside or outerblade in relation to the opposing, second scissor blade 34 that may beconsidered, although not limited to, an inside or inner blade.

With reference to FIG. 2, in some embodiments, each of the first andsecond scissor blades 32, 34 has a profile 36 following a curve definedby a polynomial, such as a parabola. Desirably, the relationship betweenthe curves of the first and second blades creates continuous bias forcebetween the blades as the scissor assembly 30 is opened and closed.

Referring now to FIG. 3A, one embodiment of scissor blade 32, 34 for usein embodiments of laparoscopic scissor instrument is illustrated. Asingle scissor blade 32, 34 is illustrated as it is contemplated thatsubstantially identical scissor blades or manufacturing blanks forscissor blades 32, 34 can be interchangeable in some embodiments oflaparoscopic scissor instrument, thus reducing manufacturing andinventory costs. However, it is contemplated that in some embodiments,the first and scissor blades can include certain variations with respectto one another. For example, in some embodiments the profile 36discussed above can be different between the first and second blade.Also, in some embodiments, the locations and geometries of the variousportions and protrusions discussed below can be different for the firstand second blade. In the illustrated embodiment, the scissor blade 32,34 has an interface surface 60, an opposing surface 62 opposite theinterface surface 60, a distal, cutting portion 64, and a proximal,actuation portion 66. The scissor blade 32, 34 can further include apivot 68 and an actuation protrusion 70 on the actuation portion 66thereof. In the illustrated embodiment, the pivot 68 extends from theopposing surface 62 of the actuation portion 66, and the actuationprotrusion 70 extends from the interface surface 60 of the actuationportion 66.

FIG. 3A illustrates an embodiment of scissor blade 32, 34 having a pivot68 comprising a pivot protrusion. In some embodiments, the pivotprotrusion can be formed on the scissor blade 32, 34. In otherembodiments, the protrusion can be adhered to the scissor blade.

Desirably, the pivot protrusions extending from the opposing surfaces 62of the scissor blades 32, 34 leave a clearance between the scissorblades 32, 34 to allow a relatively long operational stroke of theactuation mechanism as there is no pivot pin extending through (andbetween) both scissor blades 32, 34 in an assembled scissor assembly.Advantageously, a relatively long operational stroke can allow theactuation mechanism to be configured to deliver a relatively largeamount of leverage to the scissor blades 32, 34, allowing multipletissue types to be cut. Additionally, the relatively long operationalstroke can allow the actuation mechanism and handle assembly to beconfigured to allow for a relatively long movement of the movablehandle, thus providing enhanced fine control of the position of thescissor assembly.

In some embodiments, it can be desirable to manufacture the scissorblades 32, 34 with a process that involves relatively few low costmanufacturing steps in order to minimize cost. Accordingly, it can bedesirable to form the scissor blades 32, 34 with a stamping processforming the cutting profile, which, in some embodiments, is parabolic,the pivot, and the actuation protrusion. A grinding or honing operationcan then form a cutting edge 72 on the scissor blade 32, 34. In thestamping process, the pivot protrusion can be formed using asemi-perforation process. In other embodiments, the pivot protrusionand/or the actuation protrusion can be adhered or welded to the scissorblade 32, 34 after the initial forming of the scissor blade 32, 34.

With reference to FIG. 3B, another embodiment of scissor blade 32′, 34′for use in a laparoscopic surgical instrument is illustrated. In theillustrated embodiment, the scissor blade 32′, 34′ comprises aninterface surface 60′, an opposing surface 62′, a cutting portion 64′,an actuation portion 66′, and an actuation protrusion 70′ substantiallyas described above with respect to the scissor blade 32, 34 of FIG. 3A.However, in the illustrated embodiment, the scissor blade 32′, 34′ ofFIG. 3B includes a pivot 68′ comprising a pivot aperture adapted toreceive a pivot pin 74′ or rivet therein. As discussed above, the pivotpin 74′ (FIG. 4B) can extend between the pivots 60′ of each scissorblade 32′, 34′ and pivotably couple the scissor blades 32′, 34′ to oneanother and to the elongate shaft 10. This pivot pin 74′ arrangement canshorten the operational stroke of the actuation mechanism relative tothe scissor blade 32, 34 of FIG. 3A.

With reference to the scissor blades of FIGS. 3A and 3B, each of thefirst and second scissor blades 32, 34, 32′, 34′ has a cutting edge 72,72′ that is ground at an angle (FIGS. 4A, 4B). The cutting edges 72, 72′extend from the actuation portion 66, 66′ of each of the first andsecond scissor blades 32, 34, 32′, 34′ along an edge of the cuttingportion 64, 64′ of each of the first and second scissor blades 32, 34,32′, 34′. The cutting edge 72 of the first blade 32, 32′ and cuttingedge 72 of the second blade 34, 34′ overlap each other and shear or cutacross each other during actuation of the scissor assembly. As theactuation mechanism 40 translates through the elongate shaft 10 during aclosing stroke, the point of contact or cut point progressively travelsalong the cutting edges 72 from a proximal portion to a distal portionof the cutting edges 72.

With reference to FIGS. 3A and 3B, the actuation portion 66, 66′ of eachof the first and second scissor blades 32, 34, 32′, 34′ can have anactuation protrusion 70, 70′ that can connect the respective blade tothe actuation mechanism 40. In some embodiments, the actuationprotrusion 70, 70′ comprises a projection, such as a post or pin. Theprojection can extend from the actuation portion 66, 66′ of each of thefirst and second blades 32, 34, 32′, 34′ to couple the blades to cammingslots in the actuation mechanism 40.

With reference to FIGS. 4A, 5A, and 6, the actuation mechanism 40 cancomprise an actuation shaft 42 having a proximal end and a distal endand a scissor actuator 44 at the distal end of the actuation shaft 42.In the illustrated embodiment, the scissor actuator 44 is a fork design.With the fork design, an actuation slot 46 can be formed on each forkmember of the scissor actuator 44. The actuation portion 66 of theblades can be operatively coupled to the actuation mechanism 40. With afork design scissor actuator 44, the actuation protrusion 70 of thefirst scissor blade 32 can be positioned in the an actuation slot 46 onone fork member of the scissor actuator 44 and the actuation protrusion70 of the second scissor blade 34 can be positioned in the actuationslot 46 on the other fork member of the scissor actuator 44.

In some embodiments, the actuation slot 46 can extend transverse to, orin a curved arrangement relative to a longitudinal axis of the scissoractuator 44. The geometry of the actuation slot 46 can define anactuation profile for the scissor assembly. For example, a relativelysteep slope of the actuation slot 46 relative to the longitudinal axisof the scissor actuator 44 can indicate an actuation profile with arelatively short stroke of the actuator and corresponding rapid openingand closing of the scissor blades 32, 34. A relatively shallow slope ofthe actuation slot 46 relative to the longitudinal axis of the scissoractuator 44 can indicate a relatively long actuation stroke andrelatively high leverage and slow opening and closing of the scissorblades. A curved actuation slot 46 can desirably have a relativelyshallow slope over portions of blade travel and a relatively steepstroke over other portions of blade travel. For example, with a curvedactuation slot 46, the blades could be initially rapidly advancedtowards one another for rapid initial closing of a closing actuation,then slowly advanced towards one another for a subsequent portion of aclosing actuation. Thus, in a scissor device having a curved slotconfiguration, the scissor blades could be quickly advanced towardstissue therebetween, then more slowly advanced once the blades havecontacted the tissue therebetween to provide relatively high leverageand fine control while cutting the tissue.

With continued reference to FIGS. 4A, 5A, and 6, the scissor blades 32,34 can be pivotally coupled to the elongate shaft 10 by pivot 68 such asa pin or post on the scissor blades 32, 34. The pivot 68 on each bladecan engage with a corresponding aperture 16 formed in the distal end 14of the elongate shaft 10. Thus, the engagement of the pivots 68 of eachblade 32, 34 with the elongate shaft 10 allows the blades 32, 34 topivot about the pivot 68 when the scissor assembly 30 is actuatedbetween the open and closed configurations. When the actuation mechanism40 is moved in one direction, the actuation protrusions 70 of each ofthe blades 32, 34 will cam against their respective actuation slots 46on the actuation mechanism 40.

In some embodiments, the actuation mechanism 40 may be a single integralcomponent, or, in other embodiments may have multiple pieces assembledtogether. With continued reference to FIGS. 4A, 5A, and 6, in someembodiments, the scissor actuator 44 includes a fork design includingfork members each comprising a separate flanking plate 48. In someembodiments, the flanking plates 48 can each be coupled with a distalend of the actuation shaft 42. A proximal portion of each of theflanking plates can be adapted to mate and couple with a distal portionof the actuation shaft 42, and a distal portion of each of the flankingplates 48 can be adapted to mate with and actuate one of the scissorblades 32, 34. In some embodiments, each of the flanking plates 48 iscoupled to the actuation shaft 42 by heat staking. In other embodiments,each of the flanking plates can be coupled to the actuation shaft 42 bypress-fit, fastener, adhesive, or another mechanical or chemicalprocess. The flanking plates 48 can include one or more apertures,slots, recesses, grooves, or other feature to facilitate coupling of theflanking plates to the actuation shaft 42.

In some embodiments, the scissor actuator 44 of the actuation mechanism40 can be configured to apply a biasing force to the scissor assembly30. Advantageously, a biasing force on the scissor assembly 30 canmaintain a cutting contact between cutting edges 72 of the first andsecond scissor blades 32, 34 throughout the range of motion of thescissor assembly 30 from the open position to the closed position. Withreference to FIGS. 4A, 5A, and 6, in the illustrated embodiment, thefork design of the scissor actuator 44 can be configured such that theflanking plates 48 apply a biasing force to the scissor assembly 30. Inthe illustrated embodiment, each flanking plate 48 includes a bend 49 orknuckle. When the flanking plates 48 are coupled to the actuation shaft42 to form the scissor actuator 40, the bends 49 of the flanking plates48 bear on one another such that an outward biasing force is applied tothe actuation portions 66 of the scissor blades 32, 34 (FIG. 5). Thisoutward biasing force on the actuation portions 66 proximal of the pivot68 tends to bias the cutting portions 64 of the scissor blades 32, 34,towards one another. Thus, the ability of the scissor assembly to cutvarious tissue types is enhanced.

With reference to FIGS. 4B and 5B an actuation mechanism 40′ forcoupling to a laparoscopic scissor instrument having pinned pivotingblades, such as those illustrated in FIG. 3B is illustrated. In theillustrated embodiments, the actuation mechanism 40′ includes anactuation shaft 42′ coupled to a scissor actuator 44′, substantially asdiscussed above with respect to the embodiment of FIGS. 4A, 5A, and 6.The scissor actuator 44′ includes an actuation slot 46′ formed at adistal end thereof. In the illustrated embodiment, the scissor actuator44′ comprises a forked design having two flanking plates 48′ each havingan actuation slot 46′ formed therein. However, each flanking plate 48′also includes a pivot slot 47′ adapted to receive the pivot pin 74′.Accordingly, the actuation slot 46′ of the scissor actuator 44′ of FIGS.4B and 5B is relatively short compared to the actuation slot 46 of thescissor actuator 44 of FIGS. 4A, 5A, and 6. Thus, a scissor instrumenthaving pinned-pivot scissor blades (such as those illustrated in FIGS.4B and 5B) tends to have a shorted actuation stroke than a scissorinstrument having pin-less scissor blades (such as those illustrated inFIGS. 4A, 5A, and 6).

With continued reference to FIGS. 4B and 5B, with the flanking plates48′ coupled to the actuation shaft 42′, the distal portions of theflanking plates 48′ are spaced from each other such that the actuationportions 66′ of each of the first and second scissor blades 32′, 34′ maybe positioned between distal portions of the flanking plates 48′. Thisspaced arrangement of the flanking plates 48′ differs from thebias-generating bends 49 of the flanking plates 48 of the scissoractuator 44 of FIGS. 4A, 5A, and 6.

With continued reference to FIGS. 4B and 5B, as noted above, the distalportion of each of the flanking plates 48′ has agenerally-longitudinally extending pivot slot 47′ that providesclearance for the pivot pin 74′ as the actuation mechanism 40′ is moveddistally and proximally within the elongate shaft 10. Desirably, thepivot slots 47′ can be sufficiently long to provide for a full strokelength of the scissor assembly 30′.

With continued reference to FIGS. 4B and 5B each of the flanking plates48′ also has a slanted or curved actuation slot 46′ into which theactuation protrusion of the respective scissor blade 32′, 34′ can bepositioned. The actuation slots 46′ extend transversely to each other tofacilitate opening and closing of the scissor blades 32′, 34′ as theactuation mechanism 40′ translates distally and proximally within theelongate shaft 10.

With continued reference to FIGS. 4B and 5B, as discussed above, theflanking plates 48′ may be coupled to the actuation shaft 42′ by methodssuch as heat staking, fasteners, and adhesive. The flanking plates 48′and the actuation shaft 42′ may have mating features, such as a raisedprojection for mating into an aperture, to facilitate proper positioningof the flanking plates 48′ in relation to the actuation shaft 42′.Similarly, the flanking plates 48′ and actuation shaft 42′ may havefeatures, such as angled surfaces at the proximal end of the flankingplates that conform to a surface on the actuation shaft 42′, forensuring that each flanking plate 48′ is positioned on the proper sideof the actuation shaft 42′ and oriented in the proper position.

Advantageously, in a laparoscopic instrument, a scissor assembly 30, 30′having pins on scissor blades 32, 34, 32′, 34′ to mate with a slottedactuation mechanism 40, 40′ can have a reduced operational height ascompared with a scissor assembly having slots formed on scissor bladesdriven by an actuated pin. Thus, desirably the scissor assemblies 30,30′ described herein can be configured such that their operationalheight is smaller than a diameter of the elongate shaft 10. Accordingly,during an open or close stroke of the scissor assembly 30, 30′,substantially no portion of the scissor blades 32, 34, 32′, 34′protrudes beyond the diameter of the elongate shaft 10. Accordingly, thescissor assemblies described herein advantageously have a reduced“wingspan,” and thus a reduced risk of interfering with tissue ordistorting an elastomeric sheath around the elongate shaft.

While various methods of manufacturing the blades of FIG. 3A arediscussed above, it is appreciated that there are numerous methods andprocesses of manufacturing the blades that can be used in addition to orin combination with the methods discussed above. For example, in someembodiments, the blades 32, 34, 32′, 34′ can be formed from conventionalstamping and then heat treated. In other embodiments, the blades 32, 34,32′, 34′ can be formed from a blank of pre-hardened material and thenEDM cut, waterjet cut, laser cut or even machined to obtain the finalshape. It should be noted that the protrusions, projections or pins ofthe actuation portions of the blades 32, 34, 32′, 34′ can be formeddirectly onto the blades, or they can be added to the blades 32, 34,32′, 34′ as a separate component.

Protrusions or pins that are made as separate components from the bladescan be attached to the blades in any one or a combination of ways. Forexample, in various embodiments, the protrusions can be press-fitted,swaged, threaded and/or welded to the blades 32, 34, 32′, 34′. Tomanufacture the pin as part of the blades 32, 34, 32′, 34′, a multitudeof processes can be used. A sheet of material can be stamped or machinedto include a pivot 68′ hole as well as the actuation protrusion 70′ pinor a pivot 68 protrusion and actuation protrusion 70. The sheet can thenbe heat treated and sent to a form grinder, which can grind one profileof the blade 32, 34, 32′, 34′. The ground plate can then be sent to beEDM cut and the second profile can be cut out. This type of process canyield numerous components, with the actuation protrusion pin 70, 70′ andpivot 68 protrusion integrally located, for relatively low cost.

There are also additional processes that can yield the entire part froma minimum number of operations. These can include, but are not limitedto, metal injection molding (MIM), casting, and powder metallurgy (PM).The final blade can also then be sent to be sharpened or otherpost-processing.

The following is a discussion of the pin and slot design of thelaparoscopic scissor instruments described herein, where there are anumber of advantages which can be realized. For example, the proximal,actuation portion 66, 66′ of each blade 32, 34, 32′, 34′ has arelatively reduced area. In this manner, very little or no part of theblades 32, 34, 32′, 34′ of the scissor assembly 30, 30′ extend beyondthe diameter of the elongate shaft 10 during actuation of the scissorassembly 30, 30′. This reduces the risk of substances catching on theblades 32, 34, 32′, 34′ during scissor use and likewise reduces the riskthat a sheath such as shrink tubing found on scissors would be deformedduring scissor use.

With reference to FIG. 7, to facilitate manufacturing of the actuationmechanism 40, 40′, the actuation shaft 42, 42′ may be made in two ormore shaft portions 52, 54. If made in separate shaft portions 52, 54,the shaft portions 52, 54 should be coupled by a connection 56 that canwithstand two or more times the maximum service tension of the actuationmechanism 40, 40′. For example, if the maximum service tension istwenty-eight pounds, then the connection 56 should desirably be able towithstand tension of fifty-six pounds.

With continued reference to FIG. 7, in one embodiment, a connection 56having a sequential barbed configuration is illustrated. The connection56 has a shape similar to a fir tree, on a first actuation shaft portion52 that mates to a mating female portion on a second actuation shaftportion 54. The barbs of the “fir tree” may be sequentially smaller fromthe base to the tip. In this configuration, the female portion may tendto open or separate when tension is applied to the actuation shaft 42,42′. To prevent this opening, the mating ends may each include a maleportion and a female portion so that the end of the male mating portionof each piece of the actuation rod is covered by the female matingportion of the adjoining piece of the actuation rod. The mating ends mayalso be configured to snap-fit together, such as by a slight mismatch atthe parting lines of the pieces of the actuation rod. While theconnection 56 is illustrated as a sequential barbed connection, it iscontemplated that in other embodiments, other connection types can beused to connect portions of actuation shafts in laparoscopic scissorinstruments described herein.

With reference to FIGS. 8A and 8B, to maintain the position of theelongate shaft 10 longitudinally in relation to the handle assembly 20,a proximal portion of the elongate shaft 10 may have a retention member18, 18′ projecting radially therefrom that fits into a retention cavity26, 26′ in the handle assembly 20, 20′.

FIG. 8A illustrates one embodiment of retention member 18 comprising aretention clip. The retention clip can be secured to the elongate shaft10 in slots formed in an outer surface of the shaft. The retention clipcan maintain a longitudinal position of the elongate shaft relative tothe handle assembly 20 by interfacing with a retention cavity 26 thatcan be formed of a first retention rib positioned proximally to theretention clip and a second retention rib positioned distally to theretention clip. This interface between retention member 18 and retentioncavity 26 allows the elongate shaft 10 to be rotated relative to thehandle assembly about a longitudinal axis of the elongate shaft 10, butrestricts the elongate shaft 10 from being moved axially with respect tothe handle assembly about the longitudinal axis.

FIG. 8B illustrates another embodiment of retention member 18′ for usein some embodiments of laparoscopic scissor instrument. The retentionmember 18′ comprises a retention collar that can be attached onto theelongate shaft 10 by one or a combination of coupling techniques, suchas fasteners, adhesives, and mating protrusions and apertures. In theillustrated embodiment, the collar is made from two or more identicalpieces coupled together around the tube of the shaft. The retentioncollar 18′ can engage with a retention cavity 26′ formed in the handleassembly 20′ such that the elongate shaft 10 is rotatable with respectto the handle assembly 20′, but axial movement of the elongate shaft 10with respect to the handle assembly 20′ is restricted.

With reference to FIGS. 9A and 9B, various embodiments for coupling theactuation mechanism 40, 40′ to the movable handle 24 of the handleassembly 20 are illustrated. FIG. 9A illustrates a first embodiment inwhich a first actuation disc 80 and a second actuation disc 82 areformed on the proximal end of the actuation shaft 42, forming a space 84therebetween. The actuation discs 80, 82 can be integrally formed withthe actuation shaft 40 or can be joined thereto by mechanical orchemical fastening or adhesive. In the illustrated embodiment, theactuation discs 80, 82 can have different sizes such that for example,the first actuation disc 80 has a larger diameter and thickness than thesecond actuation disc 82. In some embodiments, it can be desirable thatat least one of the actuation discs 80, 82 has a diameter large enoughto interfere with a wall of the handle assembly to limit lateralmovement of the actuation mechanism transverse to the longitudinal axisof the elongate shaft 10. In other embodiments, the actuation discs 80,82 can be substantially the same size and shape, or can have othervariations in size and shape than the illustrated embodiment. (Forexample, in some embodiments, the second actuation disc 82 can bethicker and have a larger diameter than the first actuation disc 80).

With continued reference to FIG. 9A, in the illustrated embodiment, aretention clamp 86 is formed on the movable handle 24 and engages withat least one of the discs 80, 82, and the space 84 such that movement ofthe movable handle axially slides the actuation shaft 42 within theelongate tube 10. The retention clamp 86 can include gripping flanges 88adapted to engage at least one of the discs 80, 82, and the space 84 andsidewalls 92 adapted to maintain the coupling between the actuationshaft 42 and the movable handle 24. Desirably, the retention clamp 86can be sized and configured to perform repeated scissor actuation cyclescutting various tissue types without fracturing, failing, or slippingoff of the actuation discs 80, 82. In some embodiments, the retentionclamp 86 can have a rounded profile to reduce stress concentrations atcurved portions thereof.

Advantageously, the disc shapes are relatively simple to manufacture.Furthermore, the actuation disc assembly illustrated in FIG. 8A isrelatively low profile and allows rotation of the actuation mechanism 40with respect to the handle assembly 20 about the longitudinal axis ofthe elongate shaft 10.

FIG. 9B illustrates another embodiment of coupling between the actuationmechanism 40′ and the movable handle 24. The coupling includes anenlarged proximal end such as an actuation ball 80′ adapted to mate to aretention clamp on the movable handle. The actuation ball 80′ can beintegrally formed with the actuation shaft 42′, or can be joined theretoby other mechanical or chemical coupling such as a fastener or adhesivecoupling. Thus, the actuation ball 80′ can fit into a mating groove orcavity formed in the retention clamp to provide a rotatableball-and-socket joint.

With reference to FIG. 10, a distal end of various embodiment oflaparoscopic scissors is illustrated with a sheath 15, such as anelectrically insulating shrink tube disposed about the elongate shaft10. As shown in FIG. 10, and as further discussed above, advantageously,the scissor assembly 30 can be configured such that an operationalheight of the scissor assembly is smaller than a diameter of theelongate shaft 10 such that the scissor blades 32, 34 remain insidediameter of the elongate shaft, and the sheath 15 is not distorted ordistended during operation of the scissors.

With reference to FIG. 11, in some embodiments, the laparoscopicscissors can include a rotatable elongate shaft such that a user canrotate the scissor assembly 30 as desired during use. In someembodiments, the elongate shaft can have infinite 360 degree rotationrelative to the handle assembly. In other embodiments, it can bedesirable to have rotation stops to limit the rotation of the elongateshaft to a predetermined range. The laparoscopic scissors can include arotational knob 90 coupled to the elongate shaft 10 allowing theelongate shaft 10 and scissor assembly 30 to rotate relative to thehandle assembly 20 about the longitudinal axis of the elongate shaft 10.As discussed above, the couplings between the handle assembly and theelongate shaft 10 can be configured to allow rotation therebetween aboutthe longitudinal axis of the elongate shaft 10.

Many alterations and modifications may be made by those having ordinaryskill in the art without departing from the spirit and scope of theinvention. For example, various combinations and subcombinations ofcertain features and aspects of the various embodiments described abovecan be made to form certain other embodiments of scissor within thescope of the described laparoscopic instrument. For these reasons, theabove description should not be construed as limiting the devicesdescribed herein, but should be interpreted as merely exemplary of theembodiments. Accordingly, the scope of the present devices should bemade in accordance with a fair reading of the claims that follow.

What is claimed is:
 1. A laparoscopic scissor instrument comprising: anelongate tube having a proximal end and a distal end, the elongate tubecomprising a pair of apertures through the tube at the distal end; ascissor assembly positioned at the distal end of the elongate tube, thescissor assembly comprising: a first scissor blade pivotally coupled tothe distal end of the elongate tube at the pair of apertures, the firstscissor blade comprising a distal cutting portion and a proximalactuation portion; and a second scissor blade pivotally coupled to thedistal end of the elongate tube at the pair of apertures, the secondscissor blade comprising a distal cutting portion and a proximalactuation portion; and an actuator axially slidable in the elongatetube, the actuator comprising: an actuation shaft having a proximal endand a distal end; a first flanking plate coupled to the distal end ofthe actuation shaft; and a second flanking plate coupled to the distalend of the actuation shaft, the first and second flanking platespositioned between the actuation portions of the first and secondscissor blades and operatively engaging the actuation portions of thefirst and second scissor blades, the first and second flanking platesspaced apart from one another by a void therebetween, and the first andsecond flanking plates generating spring force therebetween to bias theactuation portions of the first and second scissor blades radiallyoutward.
 2. The instrument of claim 1, wherein the first scissor bladecomprises a pivot protrusion pivotally coupling the first scissor bladeto a first aperture of the pair of apertures of the distal end of theelongate tube.
 3. The instrument of claim 2, wherein the pivotprotrusion is integrally formed with the first scissor blade.
 4. Theinstrument of claim 3, wherein the pivot protrusion is formed by asemi-perforation process during a stamping operation.
 5. The instrumentof claim 2, wherein the second scissor blade comprises a second pivotprotrusion pivotally coupling the second scissor blade to a secondaperture of the pair of apertures of the distal end of the elongatetube.
 6. The instrument of claim 1, wherein the first flanking plate andthe second flanking plate each comprise a bend, and the bend of thefirst flanking plate bears on the bend of the second flanking plate togenerate the spring force therebetween.
 7. The instrument of claim 1,wherein the first scissor blade comprises a first actuation protrusionextending from the actuation portion thereof, and the first flankingplate comprises a first actuation slot extending therethrough, the firstactuation protrusion being operatively engaged in the first actuationslot.
 8. The instrument of claim 1, wherein the second scissor bladecomprises a second actuation protrusion extending from the actuationportion thereof, and the second flanking plate comprises a secondactuation slot extending therethrough, the second actuation protrusionbeing operatively engaged in the second actuation slot.
 9. Theinstrument of claim 1, wherein the first flanking plate and the secondflanking plate are each coupled to the actuation shaft by heat staking.10. The instrument of claim 1, wherein the first scissor blade and thesecond scissor blade are formed by a stamping process.
 11. Theinstrument of claim 1, wherein the elongate tube comprises a metallicmaterial.
 12. The instrument of claim 11, further comprising anelectrically insulating sheath disposed around the elongate tube. 13.The instrument of claim 1, wherein the pair of apertures through theelongate tube are disposed at a substantially flattened segment at thedistal end of the elongate tube.